Comprehensive mass transfer analysis of CO2 absorption in high potential ternary AMP-PZ-MEA solvent using three-level factorial design

Mass transfer of CO2 absorption in 2-amino-2-methyl-1-propanol (AMP) - piperazine (PZ) - monoethanolamine (MEA) was statistically investigated in terms of overall mass transfer coefficient (K(G)a(v)) and CO2 removal percentage. The parameters of interest were lean solvent flux (A), rich gas flux (B), CO2 loading in the lean solvent (C), and ratio of the sampling height to the total column height h/h 0 (D). From ANOVA, A was the most impactable parameter on both responses with three-quarters of the overall contribution. Regarding the three-level factorial design, a second-order polynomial increasing trend of K(G)a(v) was observed as C and/or D increased. Additionally, K(G)a(v) linearly increased as A increased but was not affected by B. On the other hand, the CO2 removal percentage linearly increased as A and/or D increased but linearly decreased as B and/or C increased. Surface analysis suggested the optimum condition for both responses at a high level of A, low level of B, low level of C, and middle level of D. In this work, D was statistically investigated and included in the predictive correlation for K(G)a(v) for the first time. The main advantage of the proposed correlation over the recently reported correlations was that it did not require a measurement of CO2 partial pressure along the column height. For each amine component in the blend, (i) AMP played a positive key role in cyclic capacity and solvent regeneration duty, (ii) PZ enhanced transfer rate, and (iii) MEA elevated total amine concentration. As a result, 1.5:1.5:3 was recommended due to (i) elevations of 68.2% K(G)a(v), 14% CO2 removal percentage, 15.1% absorption capacity, and 66.7% cyclic capacity and (ii) reduction of 50% regeneration duty compared with 5 M MEA. With respect to the other literature-reported solvents, AMP-PZ-MEA is very competitive in terms of transfer coefficient, cyclic capacity, and solvent regeneration heat duty.

Automated summary

This study statistically investigated the mass transfer of CO2 absorption in 2-amino-2-methyl-1-propanol (AMP) - piperazine (PZ) - monoethanolamine (MEA), and proposed the optimal condition based on the results. The impact of different parameters on the mass transfer coefficient and CO2 removal percentage was analyzed, and linear or second-order polynomial relationships were established.